Combined line and cutoff relay for telephone systems



March 24, 1942. R,A S, WILBR 2,277,191

COMBINED'LINE AND CUT-OFF RELl FOR TELEPHONE SYSTEMS Filed Nov. 2, 1959FINDER START W fm" l l 4a? lso '74 L/NE F/NDER srARr /NVENTOR R. S.W/LBUR Patented Mar. 24, 1942 COMBNED LINE ANDl CUTOFF RELAY FORTELEPHONE SYSTEMS Ray S. Wilbur, Summit, N. J., assigner to BellTelephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application November 2, 1939,Serial No. 302,517

Claims.

This invention relates to telephone systems and more particularly to acombined line and cutoff relay structure applicable to a subscribersline for replacing the usual individual line and cut-off relays and forperforming all of the functions thereof. It is the object of the presentinvention to simplify and to reduce the cost of the individual relayequipment of subscribers lines.

To attain this object a relay of a standard type, now used extensivelyin telephone systems, is modined by the addition of two cam wheelsoperable step by step by a pawl secured to the relay armature which camsare eiective to control certain of the springs of the relay springpile-ups, other springs of the pile-ups being operable by the armaturein the usual manner, while still other springs are operable both in theusual manner and by the cam wheels. The cam wheels are secured to ashaft supported transversely of the front end of the relay core, one ofthe cam wheels having iive teeth and the other ten teeth, the latteralso serving as a ratchet wheel with which a pawl secured to thearmature cooperates. The shaft is thus rotated one-tenth of a revolutionupon each attraction of the armature.

In its normal condition, the windings of the relay are connected overnormally closed contacts of certain of its springs to the tip and ringconductors of the line so that when the line loop is closed to initiatea call, the relay armature is attracted and through the pawl carriedthereby starts to rotate the cam wheels. A tooth of the ten-toothed camwheel in its half step position rst operates certain contact springs toclose a local operating circuit serially through both windings of therelay to insure a full attraction of the relay armature. In the fullyattracted position of the armature, the local energizing circuit isopened, both windings are disconnected from the line loop and theve-tooth'ed cam wheel operates springs to connect the tip winding of therelay to the sleeve terminal of the line and operates other contactsprings to prepare a signaling circuit, which as illustrated may be thestart circuit of a line finder.

With the energizing circuits of the relay now opened, the armaturerestores engaging contact springs to complete the line-finder startcircuit or signaling circuit. The relay has now performed all of thefunctions normally performed by the usual line relay. When the startedline finder iinds the calling line, the relay is again energized by itstip winding over contact springs closed by the iive-toothed cam wheeland at tracts the armature to advance the shaft another step, thearmature in its attracted position opening the start circuit and holdingthe contact springs closed whereby the tip winding remains connected tothe sleeve terminal and is maintained energized until the connection isreleased. At this time, both windings of the relay are disconnected fromthe line loop. When the connection is released, the relay deenergizesand returns all contact springs to their normal condition. The relay hasnow performed the functions normally performed by the usual cut-offrelay;

When the line is seized as a called line, as for example over aconnector multiple, the tip winding thereof is energized over theconnector sleeve terminal and the armature in passing to its fullyattracted position advances the cam wheels, the ten-toothed cam wheelmomentarily closing a local energizing circuit through both windings ofthe relay and the five-toothed cam wheel opening contact springsincluded in the energizing circuit through the tip winding.y In itsfully attracted position, the local energizing circuit is opened atother contact springs whereby the armature is restored and closes theline-nnder start circuit. The energizing circuit through the tip windingof the relay is, however, immediately reclosed and the relay againattracts its armature advancing the shaft another step, thereby openingthe start circuit. This momentary closure of the start circuit is noteffective in this Case to start a line nder since the line-finder startrelay may be made slow to operate. The energizing circuit through thetip winding is now maintained over contact springs which were permittedto close by the second step taken by the Ve-toothed cam wheel and bothwindings are disconnected from the tip and ring conductors of the lineloop. When the connection is released, the relay releases and restoresall of its contact springs to their normal condition. Thus when the lineis seized as a called line, the relay performs all of the functionsperformed by the usual cut-01T relay.

The invention having been described in a general manner, reference maynow be had, for a more comprehensive understanding thereof', to thefollowing detailed description taken in connection with the accompanyingdrawing in which:

Fig. l is a side elevational view of a relay in which the presentinvention is embodied;

Fig. 2 is a front elevational view of the relay;

Fig. 3 shows schematically a subscribers line, a line iinder havingaccess thereto, the relay and the circuits controlled thereby in theirnormal condition;

Fig. 4 illustrates the operated position of the relay and the conditionof the circuits controlled thereby immediately following the initiationof a call on the subscribers line and the closure of the line loop;

Fig. 5 illustrates the succeeding released position of the relay and thecondition of the circuits controlled thereby at which time thelineiinder start circuit is closed; and

Fig. 6 illustrates the succeeding operated position of the relay and thecondition of the circuits controlled thereby at the time the lineterminals are seized by the line nder.

The improved relay structure is of the general type disclosed in Patent2,178,656, granted November '7, 1939 to P. W. Swenson and comprises asupporting bracket I to which the rear end of a forwardly extending core2 and a hinge bracket 3 are suitably secured, a coil 4 having twowindings surrounding the core'2, a U-shaped armature 5, the arms ofwhich are pivoted by pins 6 on the arms, of the hinge bracket 3 and theforward cross reach of which cooperates with the pole face 'I of theforward end of the cord 2, a back-stop screw 8 secured in the forwardend of the core 2 having a back-stop nut 9 thereon for adjusting thenormal air-gap between the armature and the pole face of the core, andtwo spring pile-ups I3 and II, one on either side of the coil,insulatedly supported on and secured to the mounting bracket I by screwsI2.

In accordance with the present invention, this relay structure has beenmodied by the addition of two cam wheels I3 and I4 secured respectivelyon the opposite ends of a shaft I5 which is rotatably mounted in abracket IE extending transversely across the forward end of the relaycore and secured to the core 2 bythe screw Il. The cam wheel I3, whichis provided with ten teeth and serves also as a ratchet wheel by meansof which both cam wheels may be rotated step by step under the controlof spring pawl I8 secured to the end of the armature 5 by screw I9.cooperates with a stud 20 of insulating material secured to the contactspring 2|. The cam wheel I4 has ve teeth and cooperates with a stud 22of insulating material secured to the contact spring 23 which passesfreely through a hole in its mate spring 24. Normally the contacts ofsprings 23 and 24 are in engagement. Cam wheel I4 also cooperates with astud 25 secured to the spring 26 which spring mates with a spring 21 andis normally out of contact therewith.

The active contact springs 28 and 3U are normally in engagement withtheir mate springs 29 and 3| and are interconnected by the stud 32 ofinsulating material staked thereto and passing freely through holes insprings 23 and 3|. The active spring 33 is normally in engagement withits mate spring 34 and has staked thereto a stud 35 which passes freelythrough a hole in spring S4 into engagement with the inner surface ofthe end oi' armature 5. The upper end of stud 35 is positioned forengagement with the lower end of stud 32 so that when the armature isattracted, the stud 35 is moved to operate spring 33 and by its engagement with stud 32 also operates springs 23 and 33. The active contactspring 35 cooperates with a back contact spring 38 with whichv it isnormally engaged and with a front contact spring 31 and has stakedthereto an insulating stud 33 which extends freely through a hole inspring 38. Positioned immediately below the lower end of stud 39 is astud 44 which is staked to spring 26 and passes freely through a hole inspring 2l. A stud 4I is secured to the armature with its upper endpositioned beneath the lower end of stud 43 whereby when the armature isattracted the stud 4I engages the stud 43 to operate spring 23 and stud4) engages stud 39 to operate spring 36.

Having now described the structiu'e of the improved relay, itsapplication to a telephone system will be discussed. Referring rst toFig. 3, a subscribers substation 42 is schematically disclosed which isconnected over the tip line conductor 43 and the ring line conductor 44to terminals appearing in the bank of a line nder 45, schematicallyillustrated by the set of brushes, and also to terminals of terminal set45 of a connector bank. Normally the cam wheels and contact springs arein the condition illustrated in Fig. 3. lt will now be assumed that thesubscriber at substation 42 initiates a call by removing the receiverfrom the switchhook whereupon a circuit is established from groundthrough battery 4l, the upper winding of relay coil 4 over spring 353and its back contact spring 38, tip conductor 43 over the substationloop, ring conductor 44, spring 33 and its mate spring 34, through thelower winding of coil 4 to ground. The relay windings are therebyenergized and attract the armature 5.

By the movement of the armature to its fully attracted position asdisclosed in Fig. 4, the pawl I8 secured to the armature advances theratchet wheel I3 one tooth or one step. At its half step position thestud Z3 rides up upon the top of a tooth of the cam wheel and causes theengagement of spring 2| to which the stud is secured with spring 23thereby establishing a local operating circuit for the windings of therelay extending from the ungrounded terminal of battery 4'! through theupper winding of the coil 4 over springs 29 and 2| through the lowerwinding of the coil 4 to the grounded terminal of the battery. Thiscircuit insures that the windings will be maintained energized until thearmature is fully attracted since upon the movement of the armature, thestud 35 engaged thereby will open the line loop operating circuit forthe relay windings by moving spring 33 out of engagement with spring 34.

When the armature reaches its fully attracted position as illustrated inFig. 4, the stud 23 drops down into the depression between two teeth ofcam wheel I3; the upper end of stud 35 is engaged against the lower endof stud 32 to move springs 28 and 3|] out of engagement with their matesprings 29 and 3|; a tooth of cam wheel I4 depresses stud 22 to movespring 23 out of engagement with spring 24 and a second tooth of camwheel I4 raises stud 25 to engage spring 25 with spring 2l and themovement of spring 25 engages its stud 43 with stud 39 to disengagespring 3S from spring 3B and to engage it with spring 3l. Upon thedisengagement of springs 35 and 33, the previously traced connection ofthe upper winding of coil 4 to tip conductor 43 is opened and since theconnection of the lower winding of coil 4 to ring conductor 44 wasopened upon the disengagement of springs 33 and 34, both windings of thecoil 4 are now disconnected from the line loop. Since also springs 2|and 23 are at this time out of engagement and the local energizingcircuit through the relay windings is therefore opened, the relayreleases its armature. With spring 36 now held in engagement with spring3l by a tooth of cam wheel I4, the sleeve terminal of the calling lineis marked with battery potential to indicate to the line finders havingaccess thereto that the line is in a calling condition. This potentialis applied from battery 41 through the upper winding of coil 4 oversprings 36 and 31 to terminal 48. Over springs 26 and 21 which are heldin engagement by a tooth of cam wheel I4, the line-finder start circuit49 is prepared.

Upon the release of the relay armature as just described, the cam wheelsretain their previous settings but the armature permits springs 28, 30and 33 to restore so that the circuit assumes the condition illustratedin Fig. 5. With spring 30 now in engagement with spring 3I and springs26 and 21 still held in engagement by a tooth of cam wheel I4, theline-finder start circuit is completed from ground over springs 3l and3D and over springs 21 and 26 whereupon in the well-known manner an idleline finder is started in search of the calling line. It will be assumedthat the line finder indicated by the numeral 45 is started and that,therefore, when its test brush 50 encounters sleeve terminal 48 of theline a circuit is established from ground on 'brush 53 over terminal 48,springs 31 and 36, through the upper winding of coil 4 to battery,thereby causing the attraction of the relay armature to advance the camwheels another step. The circuit now has assumed the conditionillustrated in Fig. 6.

It will be noted that the movement of the armature has now disengagedsprings, 28, 36 and 33 from their mate springs whereby the start circuitpreviously traced is opened at springs 3i) and 3|.

In the half step position of cam wheel I3, springs 2| and 29 aremomentarily engaged to close the local operating circuit through thewindings of coil 4 as previously traced, but this circuit is notnecessary at this time, since the upper winding of coil 4 is maintainedsteadily energized over the circuit previously traced to ground at thetest brush 5i). The second step advance of cam wheel I4 permits spring23 to reengage spring 24 and moves its tooth from under the end of stud25, but springs 26 and 36 are not permitted to restore since they arenow held in their operated positions by stud 4I secured to the armaturewhich is now positioned with its up-per end in engagement with the lowerend of stud 40. The relay armature is now maintained in its attracted.position by the L energization of the upper winding of coil 4 until theconnection is released and ground is removed from the test brush 50.With the springs 33 and 34 disengaged and springs 33 and 38 alsodisengaged, both windings of the coil 4 are disconnected from the lineconductors. When ground is disconnected from test brush 50, the upperwinding of coil 4 becomes deenergized and the armature releases torestore the circuit to its normal position illustrated in Fig. 3.

Should the line be seized on an incoming call by the engagement of thebrushes of a connector switch with the connector bank multiple terminalset 46 of the line and the line be at the time idle, the circuit will bein the condition illustrated in Fig. 3. A circuit will thereupon beestablished from ground in the connector switch over the sleeve terminal5I through resistance 52 to battery and in parallel with resistance 52over springs 2S and 29 or springs 23 and 24 and through the upperwinding of coil 4 to battery, whereupon the relay armature will beattracted to advance the cam wheels one step and to move the springsinto the position disclosed in Fig. 4. As previously described, in thehalf step position of cam wheel TII I3, the springs 2I and 29 areengaged to close the local operating circuit through the windings ofcoil 4 to insure that the armature will be fully attracted, since thearmature in moving to its fully attracted position disengages springs 28and 29 and the one step advance of cam wheel I4 disengages springs 23and 24 and, therefore, opens the initial operating circuit through theupper winding of coil 4. When the armature reaches its fully attractedposition with springs 28 and 29 disengaged and springs 23 and 24disengaged, the upper winding of coil 4 becomes deenergized and thearmature restores. The circuit is now in the condition illustrated inFig. 5 in which the previously traced line-under start circuit 49 isClosed from ground over springs 3I-30 and springs 21 and 26. Thiscircuit is, however, only momentarily closed since the energizingcircuit through the upper winding of coil 4 is immediately closed fromground in the connector switch over terminal 5I and springs 28 and 29and the relay armature is again attracted to disengage springs 30 and 3Iand to advance the cam wheels a second step. To insure that theline-finder start relay will not operate upon this momentary closure ofthe start circuit 49 to start a line lnder which is not required on anincoming call, the start relay may be made slightly slow to operate.

The circuit is now in the condition illustrated in Fig. 6 and the relayis maintained operated until the connection is released by theenergization of its upper winding from ground applied at the connectorover terminal 5I, springs 23 and 24 which engaged upon the second stepadvance of cam wheel I4, through the upper winding of coil 4. When theconnection is released, the relay circuit restores to the conditionillustrated in Fig. 3. Had the line been busy because of a callinitiated therefrom, in which case the circuit would be in the conditionillustrated in Fig. 6, the test brush of the connector switch wouldencounter busy ground on the test terminal 5I applied thereto overengaged springs 23 and 24, engaged springs 36 and 31, terminal 48 andbrush of the line nder.

While the invention has been disclosed in connection with a line circuitterminating in the bank of a line nder, it will be obvious that the linecould be a line of a manual exchange system in which the circuit closedover the start conductor 49 could control the lighting of a line lampand the relay would be responsive to the seizure of the line by anoperator to extinguish such line lamp.

What is claimed is:

l. A relay having a core, windings thereon, an armature cooperating withsaid core, sets of springs having contacts operable by said armature, arst energizing circuit for said windings extending over normally closedcontacts of certain of said springs, means controlled by the firstenergization of said windings over said circuit to operate certain ofsaid springs to disconnect said windings from said circuit and toconnect one of said windings to a second operating circuit, meansoperative upon the deenergization of said windings to operate certain ofsaid springs to close a signaling circuit and means operative upon thereenergization of said one winding over said second operating circuit tooperate certain of said springs to open said signaling circuit, saidwinding becoming deenergized upon the subsequent opening of said secondoperating circuit to restore all springs to their normal conditionwhereby said windings are reconnected to said rst operating circuit.

2. A combined line and cut-off relay having a core, windings thereon, anarmature cooperating with said core, sets of springs having contactsoperable by said armature, means controlled by a rst energization ofboth windings over a line loop to operate certain of said springs todisconnect said windings from said loop, to momentarily connect saidwindings in a local operating circuit, to prepare a signaling circuitand to prepare a second operating circuit through one of said windings,means operative in response to the deenergization of said windings uponthe opening of said local operating circuit to operate certain or saidsprings to close said signaling circuit and means operable upon thereenergization of said one winding over said second operating circuit tooperate certain of said springs to open said signaling circuit, said onewinding becoming deenergized upon the opening of said second operatingcircuit to restore all springs to their normal condition whereby saidwindings become reconnected to the line loop.

3. A combined line and cut-off relay having a core, windings thereon, anarmature cooperating with said core, first sets of contact springsoperable by said armature over which said windings are normallyconnected to a line loop, a rotatable shaft having carn wheels thereon,a pawl secured to said armature whereby said shaft is advanced step bystep upon successive actuations of said armature, a second set ofcontact springs momentarily operable during the rst step advance of oneof said cam wheels by the attraction of said armature in response to theclosure of the line loop to close a local energizing circuit for saidwindings, a third set of Contact springs operable by the first stepadvance oi' said other cam wheel for preparing a signaling circuit, saidarmature in its fully attracted position operating said nrst sets ofsprings to disconnect said windings from said line loop whereby upon theopening of said momentarily operated second set of springs said windingsare deenergized to release said armature, a fourth set of contactsprings closable upon the release of said armature to close saidprepared signaling circuit and a second operating circuit for one ofsaid windings prepared over one of said rst sets of springs by the iirststep advance of said other cam wheel whereby upon the closure of saidsecond circuit andl the attraction of said armature said cam wheels areadvanced a second step, said fourth set of springs are opened to disruptsaid signaling circuit and one of said first sets of springs is heldoperated to maintain said second operating circuit closed.

4. A combined line and cut-off relay having a core, windings thereon, anarmature cooperating with said core, sets of springs having contactsoperable by said armature, said windings being normally connected to aline loop over certain o1' said springs and one winding being normallyconnected to a second operating circuit over other of said springs,means controlled by a first energization of said one winding over saidsecond operating circuit to operate certain of said springs todisconnect said windings from the line loop and from said secondoperating circuit whereby said one winding becomes deenergized tooperate other of said springs to reconnect said one winding to saidsecond operating circuit whereupon said one winding again becomesenergized to operate springs whereby it is maintained energized so longas said second operating circuit is maintained closed.

5. A combined line and cut-off relay having a core, windings thereon, anarmature cooperating with said core, rst sets of contact springsoperable by said armature over which said windings are normallyconnected to a line loop, an operating circuit for one winding of saidrelay extending in parallel over second and third sets of contactsprings, a rotatable shaft having a cam wheel thereon, a pawl secured tosaid armature whereby said shaft is advanced step by step uponsuccessive attractions of said armature and means for closing saidoperating circuit whereby said armature is attracted to open said firstsets oi springs to disconnect said windings from the line loop7 to opensaid second set of contact springs and to advance said cam wheel onestep to open said third set of springs, said winding thereupondeenergizing to release said armature whereby said second set of springsis reclosed to reestablish said operating circuit whereupon saidarmature is reattracted to advance said cam wheel a second step toreclose said third set 0i springs, said operating circuit then remainingclosed until opened by said means.

RAY S. WILBUR.

